Printing plate and method of production thereof



Aug. 16, 1927.

' F. FISCHER PRINTING PLATE AND METHOD OF PRODUCTION THEREOF FiledMarchlO, 1926' omo eooooooooooo voooooooooooxowo Patented Aug. 16, 1927.

' UNITED STATES PATENT 0 FERDINAND rrscnnn, or. nnnnnv, GERMANY.

1,639,171 FFICEJ)" rnr'urme PLATE AND METHOD-or rnonocrrou rnnnnon-Application filed March 10, 1926. Serial No. 93,758.

As printing plates for socalled ofiice duplicators there are mostly usedpaper plates.

with a coating of wax orsimilar material. The use of such plates howeverentails a enumber of disadvantages.

For this reason some oflice duplicators have previously been producedwhich operate with more suitable printing plates of metal ormetallizedor metal-coated paper. These printing plates are so thin thatthey can be typed upon in an ordinary typewriter just as an ordinarysheet of paper, whereupon printing is effected by means of theprinting'plate in the usual planographic or T5" lithographic .method,for example offset process. M

Such metal printing plates have extraordinarily great advantages butsome disadvantages wer'e hitherto unavoidable.

If simply the raw metal plate is supplied to the purchaser as theprinting plate, the

purchasenin order to be able to operate ng plate to a larger scale.-

with-the plate,'mus t himself treat the print-' in-g surface in themanner well known in. the art of lithography. This includes grain --ingthe printing surface and etching before printing, which imparts to. thatpart of the printing surface, not provided wlth inscriptions, imagesorlines for printing, the capacity of rejecting printing ink when in adamp condition. I r

The production of good and -uniform graining, however, is a"very-diflicult operation on thin sheet material so that an insufficiently skilled purchaser or user will spoil a great many plates.

In order to remedy this disadvantage it has already been suggested tosupply to the purchaser from the factory completely prepared plates,that is grained and etched printing plates, which consequently when in adamp condition reject printing ink over their entiresurface. Thishowever has the disadvantage that the typing or marking of the writtenmatter causes consid *bl' ditfipecially prepared carbon papers, heattreatment and thelike. y

The invention eliminates all these difliculties, in that it suggests anovel middle course. .Accordi ng to the invention the purchaser or useris supplied with the finished grained printing plate, which however hasnot been etched, as a new article of manufacture. The purchaser need nottherefore be troubled with the difficult process of graining orroughening and is therefore not liable to spoil the plate in carryingout this operation.

On the other hand he can type upon the half finished plate as on anordinary sheet of paper, in. a typewriter and then without any up toabout 21 cm. wide and 33 cm. in length.

In the accompanying drawings there is diagrammatically illustrated oneconstructional example of the invention and a particularly advantageousmethod of production. The invention however is not limited in any waythereto.

Fig. 1 is a plan of a printing plate according to theinvention on areduced scale.

Fig. 2 is a section of a part of the print p The printing plate a isalong its two nar row sides provided with a plurality of holes 6 for thepurpose of attachment to suitable pins of the cylinder ofan ofliceduplicator, and preferably consists of an extremely thin plate of ametal suitable for lithogfiaphic purposes such as zinc or aluminum, forexample only about 0.05 to 0.06 mm. thick. For the urp'ose of moreconvenient manipulation t with a-sheet o of rial.

According to theinvention the consumer is supplied-with the sheet cut toa useful size and provided with holes I) insuch acondition thattheprinting surface is already provided with the graining oi, which forthe "sake -of clearness is shown by a thick line. The production of thisgraining of the ready out small sheets a would be efitremely diflicultinpractice. course is had, according to the invention, to specialtreatment as represented in Figs. 3 and 4, according to which aplurality of printing plates are grained in the form of a large combinedsheet or band and then cut into the separate rintingplates.

According toig'. 3 aflar'ge plate 9 is clamped in a suitable manner on arotary cylinder 1'', whose surface corresponds to is plate is coated onthe rear side'- paper or the like soft mate- For this reason rethat of aplurality of printing plates 41. Against the surface of the sheet 9 isprojected a sand blast h, for example by means of projecting wheel i,whereby the surface [S grained. The sheet 1 is then cut into i smallplates 0.

scribed in connection with Fig. 3, whereupon the band is wound upon tothe roller 15 p, in order to be then cut into plates a.

. What I claim and desire to secure by Letters Patent of the UnitedStates is As a new article of manufacture, a small printing platesuitable for lithography comprising a metallic sheet provided with acommercially grained printing surface, and of uniform thinnessthroughout to both end edges thereof, said sheet being of such thinnessas to be successfully tensioned on the cylinder of a duplicating machineby more pins and holes, the end of said sheet being provided with aseries of holes for this purpose extending transversely there across.

In testimony whereof I affix-my si nature.

FERDINAND FISC ER.

